Taking a Measurement with Your Computer

Summary

In this tutorial, Venit demonstrates how to take voltage measurements using a USB data acquisition device and LabVIEW. The device, featuring multiple analog inputs and outputs, connects to the computer via USB for both power and data transfer. Venit walks through configuring the LabVIEW environment, using the DAC Assistant to set up an analog input for acquiring a sine wave from a function generator. He shows how to configure sample rates, run continuous measurements, and visualize the data in real-time. The video provides a clear, step-by-step guide to setting up and using a basic voltage measurement system with LabVIEW.

Takeaways

• 😀 The USB data acquisition device has 16 analog input channels, 2 analog output channels, 24 digital I/O lines, and 2 counter timers.
• 😀 The device is bus-powered, meaning it receives power through the USB connection.
• 😀 The device can be easily connected to a computer, and the driver software automatically detects it once plugged in.
• 😀 LabVIEW, a graphical development environment, is used to create applications for the device.
• 😀 LabVIEW programs are built using Virtual Instruments (VIs), which consist of a Front Panel (UI) and a Block Diagram (code).
• 😀 The Front Panel allows users to interact with the device through controls like knobs, buttons, and graphs.
• 😀 The Block Diagram contains the actual graphical code, where users can implement functions such as signal analysis and loop structures.
• 😀 The Data Acquisition (DAQ) Assistant in LabVIEW simplifies the configuration of input and output channels for the device.
• 😀 Users can configure the DAQ Assistant to acquire voltage signals and choose from various sensor types like strain, pressure, and temperature.
• 😀 Continuous measurements can be configured in LabVIEW to acquire data indefinitely, with the ability to stop the acquisition using a stop button.
• 😀 The program supports real-time signal monitoring, as demonstrated by viewing a sine wave output from a function generator connected to the device.

Q & A

What is a USB data acquisition device?

A USB data acquisition device is a tool used to collect data from various sources, typically through analog and digital input/output channels. In the context of the script, this device has 16 analog input channels, 2 analog output channels, 24 digital I/O lines, and 2 counter timers.

How does the USB data acquisition device get its power?

The USB data acquisition device is powered through the USB bus itself, meaning it doesn't require a separate power supply and gets all its necessary power from the computer it's connected to.

What is LabVIEW and how is it used in this example?

LabVIEW is a graphical development environment used for system design and data acquisition. In this example, LabVIEW is used to create a program (VI - Virtual Instrument) that interfaces with the USB data acquisition device to collect and display data from an external signal source.

What is the role of the front panel in LabVIEW?

In LabVIEW, the front panel serves as the user interface where buttons, knobs, graphs, and other interactive elements are placed. These elements allow users to control and visualize the data collection process.

What is the purpose of the block diagram in LabVIEW?

The block diagram in LabVIEW is where the graphical code resides. It contains the functions, controls, and logic needed to perform tasks like data acquisition, signal analysis, and control flow (loops and conditions).

What is the DAC Assistant in LabVIEW?

The DAC Assistant is a configuration-based wizard in LabVIEW that simplifies the process of setting up data acquisition tasks, such as selecting input/output channels, setting sampling rates, and configuring other measurement parameters.

What type of sensor is being used for the measurement in this example?

In this example, a function generator is used to create a sine wave signal, which is connected to the USB data acquisition device. The sensor type chosen is an analog voltage input.

How do you visualize the acquired data in LabVIEW?

The acquired data is visualized in LabVIEW by creating a graph indicator on the front panel. This graph displays the real-time data collected from the input signal, such as the sine wave in the example.

What does the option to use continuous samples mean in LabVIEW?

Selecting continuous samples in LabVIEW means that data acquisition will happen continuously, without stopping after a fixed number of samples. This option is useful for applications where ongoing data collection is required until a stop condition is triggered.

How does the stop button function in the LabVIEW program?

The stop button in LabVIEW is used to halt the continuous data acquisition loop. Once pressed, it stops the program from acquiring further samples, effectively ending the measurement process.